// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <test_progs.h>
#include "cgroup_helpers.h"

#define TEST_NS "sock_post_bind"

static char bpf_log_buf[4096];

static struct sock_post_bind_test {
        const char                      *descr;
        /* BPF prog properties */
        const struct bpf_insn           insns[64];
        enum bpf_attach_type            attach_type;
        enum bpf_attach_type            expected_attach_type;
        /* Socket properties */
        int                             domain;
        int                             type;
        /* Endpoint to bind() to */
        const char *ip;
        unsigned short port;
        unsigned short port_retry;

        /* Expected test result */
        enum {
                ATTACH_REJECT,
                BIND_REJECT,
                SUCCESS,
                RETRY_SUCCESS,
                RETRY_REJECT
        } result;
} tests[] = {
        {
                .descr = "attach type mismatch bind4 vs bind6",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
                .attach_type = BPF_CGROUP_INET6_POST_BIND,
                .result = ATTACH_REJECT,
        },
        {
                .descr = "attach type mismatch bind6 vs bind4",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .result = ATTACH_REJECT,
        },
        {
                .descr = "attach type mismatch default vs bind4",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = 0,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .result = ATTACH_REJECT,
        },
        {
                .descr = "attach type mismatch bind6 vs sock_create",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
                .attach_type = BPF_CGROUP_INET_SOCK_CREATE,
                .result = ATTACH_REJECT,
        },
        {
                .descr = "bind4 reject all",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .domain = AF_INET,
                .type = SOCK_STREAM,
                .ip = "0.0.0.0",
                .result = BIND_REJECT,
        },
        {
                .descr = "bind6 reject all",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
                .attach_type = BPF_CGROUP_INET6_POST_BIND,
                .domain = AF_INET6,
                .type = SOCK_STREAM,
                .ip = "::",
                .result = BIND_REJECT,
        },
        {
                .descr = "bind6 deny specific IP & port",
                .insns = {
                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),

                        /* if (ip == expected && port == expected) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_ip6[3])),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
                                    __bpf_constant_ntohl(0x00000001), 4),
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_port)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
                .attach_type = BPF_CGROUP_INET6_POST_BIND,
                .domain = AF_INET6,
                .type = SOCK_STREAM,
                .ip = "::1",
                .port = 8193,
                .result = BIND_REJECT,
        },
        {
                .descr = "bind4 allow specific IP & port",
                .insns = {
                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),

                        /* if (ip == expected && port == expected) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_ip4)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
                                    __bpf_constant_ntohl(0x7F000001), 4),
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_port)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),

                        /* return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_JMP_A(1),

                        /* else return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .domain = AF_INET,
                .type = SOCK_STREAM,
                .ip = "127.0.0.1",
                .port = 4098,
                .result = SUCCESS,
        },
        {
                .descr = "bind4 deny specific IP & port of TCP, and retry",
                .insns = {
                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),

                        /* if (ip == expected && port == expected) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_ip4)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
                                    __bpf_constant_ntohl(0x7F000001), 4),
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_port)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .domain = AF_INET,
                .type = SOCK_STREAM,
                .ip = "127.0.0.1",
                .port = 4098,
                .port_retry = 5000,
                .result = RETRY_SUCCESS,
        },
        {
                .descr = "bind4 deny specific IP & port of UDP, and retry",
                .insns = {
                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),

                        /* if (ip == expected && port == expected) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_ip4)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
                                    __bpf_constant_ntohl(0x7F000001), 4),
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_port)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x1002, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .domain = AF_INET,
                .type = SOCK_DGRAM,
                .ip = "127.0.0.1",
                .port = 4098,
                .port_retry = 5000,
                .result = RETRY_SUCCESS,
        },
        {
                .descr = "bind6 deny specific IP & port, and retry",
                .insns = {
                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),

                        /* if (ip == expected && port == expected) */
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_ip6[3])),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7,
                                    __bpf_constant_ntohl(0x00000001), 4),
                        BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_6,
                                    offsetof(struct bpf_sock, src_port)),
                        BPF_JMP_IMM(BPF_JNE, BPF_REG_7, 0x2001, 2),

                        /* return DENY; */
                        BPF_MOV64_IMM(BPF_REG_0, 0),
                        BPF_JMP_A(1),

                        /* else return ALLOW; */
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
                .attach_type = BPF_CGROUP_INET6_POST_BIND,
                .domain = AF_INET6,
                .type = SOCK_STREAM,
                .ip = "::1",
                .port = 8193,
                .port_retry = 9000,
                .result = RETRY_SUCCESS,
        },
        {
                .descr = "bind4 allow all",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
                .attach_type = BPF_CGROUP_INET4_POST_BIND,
                .domain = AF_INET,
                .type = SOCK_STREAM,
                .ip = "0.0.0.0",
                .result = SUCCESS,
        },
        {
                .descr = "bind6 allow all",
                .insns = {
                        BPF_MOV64_IMM(BPF_REG_0, 1),
                        BPF_EXIT_INSN(),
                },
                .expected_attach_type = BPF_CGROUP_INET6_POST_BIND,
                .attach_type = BPF_CGROUP_INET6_POST_BIND,
                .domain = AF_INET6,
                .type = SOCK_STREAM,
                .ip = "::",
                .result = SUCCESS,
        },
};

static int load_prog(const struct bpf_insn *insns,
                     enum bpf_attach_type expected_attach_type)
{
        LIBBPF_OPTS(bpf_prog_load_opts, opts,
                    .expected_attach_type = expected_attach_type,
                    .log_level = 2,
                    .log_buf = bpf_log_buf,
                    .log_size = sizeof(bpf_log_buf),
        );
        int fd, insns_cnt = 0;

        for (;
             insns[insns_cnt].code != (BPF_JMP | BPF_EXIT);
             insns_cnt++) {
        }
        insns_cnt++;

        fd = bpf_prog_load(BPF_PROG_TYPE_CGROUP_SOCK, NULL, "GPL", insns,
                           insns_cnt, &opts);
        if (fd < 0)
                fprintf(stderr, "%s\n", bpf_log_buf);

        return fd;
}

static int bind_sock(int domain, int type, const char *ip,
                     unsigned short port, unsigned short port_retry)
{
        struct sockaddr_storage addr;
        struct sockaddr_in6 *addr6;
        struct sockaddr_in *addr4;
        int sockfd = -1;
        socklen_t len;
        int res = SUCCESS;

        sockfd = socket(domain, type, 0);
        if (sockfd < 0)
                goto err;

        memset(&addr, 0, sizeof(addr));

        if (domain == AF_INET) {
                len = sizeof(struct sockaddr_in);
                addr4 = (struct sockaddr_in *)&addr;
                addr4->sin_family = domain;
                addr4->sin_port = htons(port);
                if (inet_pton(domain, ip, (void *)&addr4->sin_addr) != 1)
                        goto err;
        } else if (domain == AF_INET6) {
                len = sizeof(struct sockaddr_in6);
                addr6 = (struct sockaddr_in6 *)&addr;
                addr6->sin6_family = domain;
                addr6->sin6_port = htons(port);
                if (inet_pton(domain, ip, (void *)&addr6->sin6_addr) != 1)
                        goto err;
        } else {
                goto err;
        }

        if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) {
                /* sys_bind() may fail for different reasons, errno has to be
                 * checked to confirm that BPF program rejected it.
                 */
                if (errno != EPERM)
                        goto err;
                if (port_retry)
                        goto retry;
                res = BIND_REJECT;
                goto out;
        }

        goto out;
retry:
        if (domain == AF_INET)
                addr4->sin_port = htons(port_retry);
        else
                addr6->sin6_port = htons(port_retry);
        if (bind(sockfd, (const struct sockaddr *)&addr, len) == -1) {
                if (errno != EPERM)
                        goto err;
                res = RETRY_REJECT;
        } else {
                res = RETRY_SUCCESS;
        }
        goto out;
err:
        res = -1;
out:
        close(sockfd);
        return res;
}

static int run_test(int cgroup_fd, struct sock_post_bind_test *test)
{
        int err, prog_fd, res, ret = 0;

        prog_fd = load_prog(test->insns, test->expected_attach_type);
        if (prog_fd < 0)
                goto err;

        err = bpf_prog_attach(prog_fd, cgroup_fd, test->attach_type, 0);
        if (err < 0) {
                if (test->result == ATTACH_REJECT)
                        goto out;
                else
                        goto err;
        }

        res = bind_sock(test->domain, test->type, test->ip, test->port,
                        test->port_retry);
        if (res > 0 && test->result == res)
                goto out;
err:
        ret = -1;
out:
        /* Detaching w/o checking return code: best effort attempt. */
        if (prog_fd != -1)
                bpf_prog_detach(cgroup_fd, test->attach_type);
        close(prog_fd);
        return ret;
}

void test_sock_post_bind(void)
{
        struct netns_obj *ns;
        int cgroup_fd;
        int i;

        cgroup_fd = test__join_cgroup("/post_bind");
        if (!ASSERT_OK_FD(cgroup_fd, "join_cgroup"))
                return;

        ns = netns_new(TEST_NS, true);
        if (!ASSERT_OK_PTR(ns, "netns_new"))
                goto cleanup;

        for (i = 0; i < ARRAY_SIZE(tests); i++) {
                if (!test__start_subtest(tests[i].descr))
                        continue;

                ASSERT_OK(run_test(cgroup_fd, &tests[i]), tests[i].descr);
        }

cleanup:
        netns_free(ns);
        close(cgroup_fd);
}